Underground hospitals were crucial during World War II to protect patients and medical workers from bombardments. And now they are being built in Syria to protect medical staff, equipment and injured civilians.
An organisation run by a group of Syrian engineers are building underground hospitals throughout Syria to keep medical workers, equipment and patients safe as the Syrian regime and Russia step up attacks in the country's northwest.
The Assad regime and its allies are reported to be planning an all out assault to take back northern Syria's Idlib province.
The UN has warned that such an offensive would lead to the "worst humanitarian catastrophe in the 21st century."
TRT World's Oubai Shahbandar reports from Gaziantep on the Syrian-Turkish border.